Barrel hardness

[MontanaRifleman]

Great stuff Neal! One thing I would like to mention is that in a conversation with Joel Kendricks, he said the not all actions are doable, at least for his process. The investment cast Howa's are not doable, but Rems and Savages are OK. Also some custom actions are not doable and he mentioned some names, but I wont repeat them in case my memory is bad. Bottom line is that anyone considering this should talk with the person who is doing the nitriding and confirm what can and can't be done by whom.

 

[Time Killer]

As promised, I checked the hardness on my new barrel. My barrel is 29 HRC straight from Broughton.
Hhmmm.

 

[Trickymissfit]

FYI, nuetral hardening on 416 SS only yields a maximum hardness of around 45 HRC.

Maximimum attainable case from nitriding is .008" in 48 hours...but is not recommended for a severe corrosion enviroment.

I happen to have my SS barrel off. I will go check the hardness and post later as I am curious as to what it is.

sounds like a 416 barrel runs parallel with a 4350 or a 4320 carbon steel blank. 47RC is about it with these steels, but you can of course run it thru a nitride process. I'd often simply use something like 4150 or 4350 pretreat steel, and the run it thru a nitride process afterwards (these pretreat steels come with a hardness of 28 - 32RC, and if you buy a good brand they are very stable). I have taken steels like 4340 and 4350, and hardened them to their max, then nitrided them.

One problem with a lot of alloys is that if you harden them to their max is that they actually become a harmonic nightmare. But you don't see nearly as much with a hard shell on it, while be a little softer in the middle. One thing that has always been in my mind with the idea of adding a hard case to a barrel is flex. It would seem to me that a hard case on the exteriors of the steel will increase rigidity; which is a very good idea
gary

 

[Trickymissfit]

Gary,

Dimensional changes I can speak of; zero. First thing he measured and a primary concern for him. we talked for quite some time about chrome linings, hard chrome plating, various other surface treatments. The fact that this one showed zero dimensional changes was a real biggie for him.

Know what you mean about these changes, too. I've had quite a few pistols and revolvers HC plated over the years, and they virtually all come back needing to be refitted and lapped in on themselves (in the case of pistols). Hard as that stuff was, redrilling holes would be a real pain.

a few years back the Army was doing some experimenting with electroless nickle processes on M16 rifles. There is one process that allows you to plate extremely accurately (.000050" steps), but is not quite as hard as regular electroless nickle. This stuff actually has teflon embedded in it! Extremely good wear properties, and a finished machined part can simply have about .0005" plated on it without a refitting of the parts. The price tag was $80 for a complete set of internals for an M16 rifle! What became of the project I don't know, as I never had the oppertunity to use any of his plating. I was thinking about doing some spindle bores on machinery, and regrinding them often took a day and a half when hard chromed.
gary

 

[jhibbard24]

Hammertyme... Great info. I haven't read much lately about nitriding for barrels or actions. i first heard about this process about 1-2 years ago through Accurateshooter.com/6mmbr.com when a top 600yd BR shooter who works for MMI Trutec was at the Shot Show. Sounded absolutlely amazing. Tried to look that up again and came up with Melonite QPQ company. I emailed Kreiger awhile back and asked them what their view was on this; they don't neccessarily endorse nitriding but they have nothing bad to say about it except for the fact that it is so hard that it is very hard to re-cut or machine it.

So is what your talking about the same as 'salt bath nitriding'? What company do you use to have your nitriding done? Is it easier to send everything through Benchmark Barrels to have them do the lapping process before and after? Does the nitriding on a carbon steel action make it corrosion resistant? Do you recomend doing actions and bolts for the smoother operation? Can you get a finish that is matte or dull? Of your 9 barrels that are shooters what brands are you using?

With the cost of carbon fiber wrapping a barrel I think it would ideal to have a barrel that would hold up to a high round count through the bore and nitriding seems to be cure. I've asked around to a few smiths that do a lot of carbon wrap barrels about trying to get all the machining done then break in the barrel and then send it off for nitriding and then to carbon wrapping, but I have not recieved any answers.

 

[hammertyme]

Yes Salt bath or Ferratic Nitriding. Below is a stainless barreled action with nut and lug Chrome Moly!

500 hours in a salt spray conducted by the military without a sign of rust in my opinion anyway qualifies as better than resistant to corrosion.

Of my nine barrels 4 are Benchmark and 5 are Savage takeoff cut to my desired length. Both Moly and stainless barrels. If you speak with Chris at Benchmark barrels he will line your right up. They are busy making barrels as always so don't forget to leave a message so he can get back to you. He has been trying to talk me into a carbon wrap Nitride barrel for a couple of weeks now.



Below is one of three target pages. The 300 Rum barrel is a closeup of Nitride and also shot 2 other targets (all 3 shot groups)with the same bullets just like pictured at 100 yards. This is what I personally call exceptional accuracy and it is from a Nitrided taakeoff barrel prior to being broke in. The blue was still in the barrel when John at 763-439-4867 took the blue off and out of the bore for Nitriding.

Neal